In an electronic ballast, a full-bridge inverter is powered from a DC voltage and provides a square-wave-like inverter output voltage. This inverter output voltage, which has a peak amplitude equal to the magnitude of the DC voltage, is applied to an instant-start fluorescent lamp via a current-limiting...http://www.google.es/patents/US5744915?utm_source=gb-gplus-sharePatente US5744915 - Electronic ballast for instant-start lamps
